This invention relates to sorters for collating sheets into sets and is particularly concerned with combined sheet inverters and sorter suitable for use with or as part of an office reproduction machine.
Frequently, it is highly desirable to reproduce a plurality of copies of the same original document or information. Moreover, if several original documents are reproduced, it is desirable to form a plurality of collated sets of copies. This may be achieved by the utilization of a sorter. Generally, the sorter comprises a plurality of bins wherein each bin is designed to collect one set of copies of the original documents. A variety of sorters are known in the art.
Although rotary sorters having bins extending radially outwardly from an axis of rotation, as shown for example in U.S. Pat. No. 3,851,872 are known, most sorters used commercially with photocopiers are of the linear type. The latter comprise a plurality of tray members which are spaced apart and extend in a linear array, which may be horizontal, as for example in U.S. Pat. Nos. 3,944,207 and 4,015,814, or vertical as in U.S. Pat. No. 3,977,667. Linear sheet sorters themselves take various well-known forms.
There are travelling gate sorters as described for example in U.S. Pat. No. 3,414,254 in which sheets are conveyed by a sheet transport past the opening of a vertical array of bins and a movable gate or feed throat traverses across the bin openings for deflecting the sheets into the respective bins in turn. In moving bin sorters such as described in U.S. Pat. Nos. 3,788,640 and 4,055,339, the bins themselves are indexed past a fixed feet throat. A third type has fixed bins and a deflector or gate associated with each bin; a sheet transport advances the copy sheets past the bin openings and the deflectors are actuated in turn to guide the sheets from the transport into the respective bins. A desirable feature of such sorters is that the bin entrance openings of the respective bins are selectively increased in size by pivoting one or both of the tray members defining the openings as a sheet is fed into it.
In some document copiers or printers, the copy sheets exit from the processor face-up. By face-up is meant in relation to a simplex sheet that the printed side of the sheet is upwards and in relation to a duplex sheet that the odd-numbered side is upwards. The problem which occurs when sheets exit in number order from a processor face-up is that they become stacked in reverse number order so that for a set of sheets 1 to n, sheet n is on the top of the stack with sheet 1 at the bottom which is inconvenient for the user. In order to overcome this problem, copiers of the kind in which the sheets are delivered from the processor in face-up condition have included a sheet inverter. Examples of this are to be found in U.S. Pat. Nos. 3,833,911, 3,944,212, 3,977,677, 4,078,789 and 4,111,410 in which it will be seen that the sheets are turned over by the inverter so that they are delivered into the copy bins face-down. In the absence of an inverter, sheets delivered to a collection tray in the order 1 to n are stacked with sheet n at the top as shown for example in U.S. Pat. No. 3,938,802.
In U.S. Pat. No. 3,833,911, sheets being conveyed face-up along a horizontal transport are inverted by deflecting them upwardly from the horizontal transport onto a vertical vacuum transport using a movable deflector and then reversing the vertical transport to return the sheet to the horizontal transport around the lower end of the vertical transport so that it is still travelling in its original direction along the horizontal transport but is now face-down. In U.S. Pat. No. 4 078 789 the vertical transport inverter is replaced by a so-called tri-roll inverter comprising three contrarotating rolls at the entrance to a chute. The sheet is deflected between the centre roll and one outer roll which drive the sheet into the chute. As the trail edge of the sheet enters the chute it becomes aligned with the nip between the centre roll and the other roll which causes the sheet to be driven out of the chute with what was the trail edge now leading and the sheet is returned to the horizontal transport still travelling in the same direction by now face-down. U.S. Pat. No. 3,944,212 shows another tri-roll inverter. Such arrangements must be inserted along the sheet conveyor path and are space-consuming and because they comprise additional parts add significantly to the cost.
U.S. Pat. Nos. 3,977,667 and 4,111,410 show arrangements in which a copy sheet inverter is combined with a sorter. In both cases the sheets are inverted by transporting them over the top of a vertical sorter array and turning them back in the opposite direction as they enter the bins so that during their travel they are turned through 180.degree.. These inverter arrangements rely on the configuration of the sorter and transport path and their relation to the copy sheet exit rolls of the processor. Such configuration and relation are not always desired or suitable.
Thus it is known from these U.S. patents to have a combined sheet inverter and sorter comprising a plurality of sheet-receiving bins, conveyor means opposite the bins for advancing sheets in one direction past the bin openings and a deflector associated with each bin for guiding a sheet into the bin.